Our project is a longitudinal study of the relationship between the characteristics and behaviors of drug-abusing parents (methadone and methadone combined with alcohol) and the behavioral, physiological, neurological, and social (e.g., mother-infant interaction) functioning of their offspring. We want to describe the course of development of offspring of drug-abusing and non-abusing parents, and to investigate the etiology of disturbances, if any, in drug abusers' offspring--whether they are related to toxicological, genetic, or social/environmental factors: (1) toxicological effects--whether drugs may have toxic effects on the fetus, and hence, on the infant's development: (2) genetic effects -whether parents reveal a neurophysiological dysfunction that may be genetically transmitted, having manifested itself in the form of drug abuse and past hyperactivity symptoms in the parents and appearing in the form of hyperkinecity and other behavioral disturbance symptoms in the offspring; (3) social/environmental effects--whether the quality of parents' interaction with their infants may significantly affect their offspring's development. We will interview the parents during pregnancy and test them on a variety of behavioral and physiological meausres, and after delivery we will see their infants several times until the age of two years. We will examine the infant's behavioral, motoric, physiological, and social responses, and observe the infant's interaction with their mothers.